Ohanna is studying what happens to the energy as a ball rolls down a ramp. What is she studying? Check all that apply.

All atoms of a specific element have the same number of _______.

Protons and electrons.

Side note: Neutron numbers may vary due to existence of istopes ((molecules that have the same number of protons (therefore its the same element) but different number of protons))

7 0

4 years ago

Whats the answer and how you got it please :-)

marta [7]

For the element chlorine to be "happy", it needs 8 valence electrons meaning it needs 8 electrons on its outer shell. So the answer would be chlorine because it has 7 valence electrons in the picture and it needs one more to be considered stable.

4 0

4 years ago

3 Na2O(aq) + 2 Al(NO3)3(aq) ----> _ Compound A + _ Compound B

Olin [163]

3Na2O(at) + 2Al(NO3)3(aq) —> 6NaNO3(aq) + Al2O3(s)

This is a double replacement reaction and NaNO3 is aqueous because Na is an alkali metal, plus nitrate is in the solution. Both of these are soluble. Al2O3 is not soluble because it does not contain any element that is soluble and is hence the precipitate.

Hope this helped!

7 0

3 years ago

How should you measure the mass of a given powdered substance??

Lelu [443]

To measure the mass of a given powdered substance do the following:
1. Zero the weighing balance, that is, put the weigh balance at zero mark.
2. Put an empty weighing paper on the balance and take its reading. Record it as X1.
3. Use spatula to put the powder you want to measure on the weighing paper on the balance. Take your reading and record it as X2.
The mass of the powered is X2 - X1.

6 0

3 years ago

A sample of potassium phosphate octahydrate (K3PO4•8H2O) is heated until 7.93 grams of water are released. How many grams did th

Gekata [30.6K]

The original sample of potassium phosphate octahydrate had a mass of 19.6 grams. When it was heated, it released 7.93 grams of water.

Further Explanation:

For every mole of the compound potassium phosphate octahydrate, there are 8 moles of water of hydration which can be removed from the crystal by heating without altering the chemical composition of the substance.

To determine how much original sample was used, the amount of water released upon heating may be used as well as the mole ratio of the water of hydration with the compound itself following the steps below:

Convert mass of water released to moles.
Use the mole ratio of water of hydration to the compound (8 mol water for every mol of potassium phosphate octahydrate) to get the moles of original sample.
Convert the moles of original sample to grams.

STEP 1: Convert 7.93 g water to moles.

$moles \ of\ H_{2}O \ = 7.93 \ g \ H_{2}O \ (\frac{1 \ mol \ H_{2}O}{18.00 \ g \ H_{2}O})\\\boxed {moles \ of \ H_{2}O \ = 0.4406 \ mol}$

STEP 2: Calculate the moles of original sample using the mole ratio: 1 mol K3PO4 8H2O : 8 mol H2O.

$moles \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 0.4406 \ mol \ H_{2}O \ (\frac{1 \ mol \ K_{3}PO_{4}\ 8H_{2}O \ }{8 \ mol \ H_{2}O})\\\\\boxed {moles \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 0.0551 \ mol}$

STEP 3: Convert the moles of original sample to mass.

$mass \ of \ K_{3}PO_{4}\ 8H_{2}O = 0.0551 \ mol \ K_{3}PO_{4}\ 8H_{2}O \ (\frac{356.3885 \ g}{1 \ mol\ K_{3}PO_{4}\ 8H_{2}O})\\ mass \ of \ K_{3}PO_{4}\ 8H_{2}O \ = 19.637 \ g$

Following the significant figures of the given, the final answer should be:

$\boxed {mass \ of \ K_{3}PO_{4}\ 8H_{2}O = 19.6 \ g}$

Learn More:

Learn more about water of hydration brainly.com/question/6053815
Learn more about mole conversion brainly.com/question/12979299
Learn more about percent hydrate brainly.com/question/12398621

Keywords: water of hydration, hydrate

4 0

3 years ago

Read 2 more answers